Evaluation of Inductor Losses on Z-source Inverter Considering AC and DC Components

This paper discusses ac and dc components of inductor losses on Z-source inverters based on theoretical calculation and experimental measurement. Winding loss with considering dc and ac components of flowing current, and core loss under dc bias application were calculated using Dowell's equation and improved Generalized Steinmetz equation (iGSE) with modification factors for dc bias. The calculated losses were verified by experiments using a 2 kW-class quasi Z-source inverter (QZSI). It is confirmed that the inductor loss is mainly caused by dc winding resistance in the discussed design, and the frequency of the main ac component of the inductor current differs from control frequency. These calculation results have good agreement with the experimental results. Therefore, it is concluded that the discussed loss calculation method can be used to design an optimal inductor for given modulation strategy and control frequency.